2,423 research outputs found

    Predictors of College Success: Symptoms of ADHD, Psychological Well-being, Appreciation of the Liberal Arts, and Understanding of College Policies

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    The present study was designed to identify predictors of college student success. More specifically, the study examined seven potential predictors for each of three measures of student success. These predictors were year in college, three academic variables and three measures of psychological well-being. It was found that self-identification of ADHD symptoms was a negative predictor of student success, whereas understanding college policies, study skills and appreciation of the liberal arts were all positive predictors of at least one of the measures of student success

    Amotivation: A Key Predictor of College GPA, College Match, and First-Year Retention

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    Two studies examined the relationships between motivational orientation, college student success, and first-year retention.  In Study 1, 523 college students completed measures of motivational orientation and student success.  Results indicated that intrinsic and extrinsic motivation were positively related to college GPA, student-university match and adjustment to college. In contrast, amotivation was negatively related to these dependent variables. Study 2 examined a mediational model in which motivational orientation, most consistently amotivation, predicted lower college student GPA and poorer college match. These, in turn predicted a decrease in first-to-second-year retention among 385 first-year college students. These results suggest that colleges may wish to address amotivation among students as a way to enhance student success and retention.

    Reassortant Pandemic (H1N1) 2009 Virus in Pigs, United Kingdom

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    Surveillance for influenza virus in pigs in the United Kingdom during spring 2010 detected a novel reassortant influenza virus. This virus had genes encoding internal proteins from pandemic (H1N1) 2009 virus and hemagglutinin and neuraminidase genes from swine influenza virus (H1N2). Our results demonstrate processes contributing to influenza virus heterogeneity

    Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B

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    We report the discovery of a widely separated (258\farcs3\pm0\farcs4) T dwarf companion to the Gl 570ABC system. This new component, Gl 570D, was initially identified from the Two Micron All Sky Survey (2MASS). Its near-infrared spectrum shows the 1.6 and 2.2 \micron CH4_4 absorption bands characteristic of T dwarfs, while its common proper motion with the Gl 570ABC system confirms companionship. Gl 570D (MJ_J = 16.47±\pm0.07) is nearly a full magnitude dimmer than the only other known T dwarf companion, Gl 229B, and estimates of L = (2.8±\pm0.3)x106^{-6} L_{\sun} and Teff_{eff} = 750±\pm50 K make it significantly cooler and less luminous than any other known brown dwarf companion. Using evolutionary models by Burrows et al. and an adopted age of 2-10 Gyr, we derive a mass estimate of 50±\pm20 MJup_{Jup} for this object.Comment: 13 pages, 2 figures, 2 tables, accepted by ApJ

    Steps in the bacterial flagellar motor

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    The bacterial flagellar motor is a highly efficient rotary machine used by many bacteria to propel themselves. It has recently been shown that at low speeds its rotation proceeds in steps [Sowa et al. (2005) Nature 437, 916--919]. Here we propose a simple physical model that accounts for this stepping behavior as a random walk in a tilted corrugated potential that combines torque and contact forces. We argue that the absolute angular position of the rotor is crucial for understanding step properties, and show this hypothesis to be consistent with the available data, in particular the observation that backward steps are smaller on average than forward steps. Our model also predicts a sublinear torque-speed relationship at low torque, and a peak in rotor diffusion as a function of torque

    Combining Ecosystem and Single-Species Modeling to Provide Ecosystem-Based Fisheries Management Advice Within Current Management Systems.

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    Although many countries have formally committed to Ecosystem-Based Fisheries Management (EBFM), actual progress toward these goals has been slow. This paper presents two independent case studies that have combined strategic advice from ecosystem modeling with the tactical advice of single-species assessment models to provide practical ecosystem-based management advice. With this approach, stock status, reference points, and initial target F are computed from a single-species model, then an ecosystem model rescales the target F according to ecosystem indicators without crossing pre-calculated single-species precautionary limits. Finally, the single-species model computes the quota advice from the rescaled target F, termed here Feco. Such a methodology incorporates both the detailed population reconstructions of the single-species model and the broader ecosystem perspective from ecosystem-based modeling, and fits into existing management schemes. The advocated method has arisen from independent work on EBFM in two international fisheries management systems: (1) Atlantic menhaden in the United States and (2) the multi species fisheries of the Irish Sea, in the Celtic Seas ecoregion. In the Atlantic menhaden example, the objective was to develop ecological reference points (ERPs) that account for the effect of menhaden harvest on predator populations and the tradeoffs associated with forage fish management. In the Irish Sea, the objective was to account for ecosystem variability when setting quotas for the individual target species. These two exercises were aimed at different management needs, but both arrived at a process of adjusting the target F used within the current single-species management. Although the approach has limitations, it represents a practical step toward EBFM, which can be adapted to a range of ecosystem objectives and applied within current management systems.publishedVersio

    The California Planet Survey. I. Four New Giant Exoplanets

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    We present precise Doppler measurements of four stars obtained during the past decade at Keck Observatory by the California Planet Survey (CPS). These stars, namely, HD 34445, HD 126614, HD 13931, and Gl 179, all show evidence for a single planet in Keplerian motion. We also present Doppler measurements from the Hobby-Eberly Telescope (HET) for two of the stars, HD 34445 and Gl 179, that confirm the Keck detections and significantly refine the orbital parameters. These planets add to the statistical properties of giant planets orbiting near or beyond the ice line, and merit follow-up by astrometry, imaging, and space-borne spectroscopy. Their orbital parameters span wide ranges of planetary minimum mass (M sin i = 0.38-1.9 M(Jup)), orbital period (P = 2.87-11.5 yr), semimajor axis (a = 2.1-5.2 AU), and eccentricity (e = 0.02-0.41). HD 34445 b (P = 2.87 yr, M sin i = 0.79 MJup, e = 0.27) is a massive planet orbiting an old, G-type star. We announce a planet, HD 126614 Ab, and an M dwarf, HD 126614 B, orbiting the metal-rich star HD 126614 (which we now refer to as HD 126614 A). The planet, HD 126614 Ab, has minimum mass M sin i = 0.38 MJup and orbits the stellar primary with period P = 3.41 yr and orbital separation a = 2.3 AU. The faint M dwarf companion, HD 126614 B, is separated from the stellar primary by 489 mas (33 AU) and was discovered with direct observations using adaptive optics and the PHARO camera at Palomar Observatory. The stellar primary in this new system, HD 126614 A, has the highest measured metallicity ([ Fe/ H] = + 0.56) of any known planet-bearing star. HD 13931 b (P = 11.5 yr, M sin i = 1.88 MJup, e = 0.02) is a Jupiter analog orbiting a near solar twin. Gl 179 b (P = 6.3 yr, M sin i = 0.82 M(Jup), e = 0.21) is a massive planet orbiting a faint M dwarf. The high metallicity of Gl 179 is consistent with the planet-metallicity correlation among M dwarfs, as documented recently by Johnson & Apps.NSF AST-0702821NASA NNX06AH52GMcDonald Observator

    Validation of predictive equations to estimate resting metabolic rate of females and males across different activity levels

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    ACKNOWLEDGMENTS The authors are sincerely grateful to all the volunteers involved in this experimental study. This research was performed in the Human Integrative Physiology Laboratory (Dept. of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA, USA). OPN is funded by a Virginia Tech Presidential Postdoctoral Fellowship, KHR by a Virginia Tech Translational Obesity Research Interdisciplinary Graduate Education Predoctoral Fellow-ship, and GZR is funded by Next Generation EU funds Margarita Salas Postdoctoral Fellowship. FUNDING INFORMATION OPN is funded by a Virginia Tech Presidential Postdoctoral Fellowship, and KHR by a Virginia Tech Translational Obesity Research Interdisciplinary Graduate Education Predoctoral FellowshipPeer reviewedPublisher PD

    Star Formation Activity in the Galactic HII Complex S255-S257

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    We present results on the star-formation activity of an optically obscured region containing an embedded cluster (S255-IR) and molecular gas between two evolved HII regions S255 and S257. We have studied the complex using optical, near-infrared (NIR) imaging, optical spectroscopy and radio continnum mapping at 15 GHz, along with Spitzer-IRAC results. It is found that the main exciting sources of the evolved HII regions S255 and S257 and the compact HII regions associated with S255-IR are of O9.5 - B3 V nature, consistent with previous observations. Our NIR observations reveal 109 likely young stellar object (YSO) candidates in an area of ~ 4'.9 x 4'.9 centered on S255-IR, which include 69 new YSO candidates. Our observations increased the number of previously identified YSOs in this region by 32%. To see the global star formation, we constructed the V-I/V diagram for 51 optically identified IRAC YSOs in an area of ~ 13' x 13' centered on S255-IR. We suggest that these YSOs have an approximate age between 0.1 - 4 Myr, indicating a non-coeval star formation. Using spectral energy distribution models, we constrained physical properties and evolutionary status of 31 and 16 YSO candidates outside and inside the gas ridge, respectively. The models suggest that the sources associated within the gas ridge are of younger population (mean age ~ 1.2 Myr) than the sources outside the gas ridge (mean age ~ 2.5 Myr). The positions of the young sources inside the gas ridge at the interface of the HII regions S255 and S257, favor a site of induced star formation.Comment: 46 pages, 14 figures, 5 tables. Accepted for publication in The Astrophysical Journa
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